In the structure of C6F5C(O)NHP(O)[N(C2H5)(C6H11)]2, in addition to N—H…O═P hydrogen bond, the oxygen atom of P═O group is involved in the P═O…π interaction (OP…Cg = 3.507(1) Å, Cg is the centroid of C6F5 ring). Moreover, a noncovalent C═O…π interaction takes part in the crystal packing, OC…Cg = 3.159(1) Å. The C═O…π interaction is the interesting feature of this structure, as a Cambridge Structural Database analysis (CSD; Allen, Acta Cryst. 2002, B58, 380–388) of 149 structures with a C(O)NHP(O)[N]2 skeleton shows that such an interaction exists only in 4 structures. The dihedral angle between the aromatic ring and the plane defined by the atoms of [C][N]C═O segment is 66.66◦. The C═O bond length in the present structure (of 1.2148(18) Å) is within the expected range for compounds with a C(O)NHP(O)[N]2 segment; however, due to the electronic effect caused by C6F5 group, it is in the region of the short bond lengths for analogous structures deposited in the CSD (1.18–1.26 Å). The P═O (1.4831(10) Å) and P—N (1.6340(12) Å and 1.6424(12) Å) bond lengths are standard for a phosphoric triamide structure and the P—N bond of C(O)NHP(O) segment (1.6980(12) Å) has an expected longer value relative to the other P—N bonds. The bond-angle sums around the tertiary nitrogen atoms (SUM = 2 × P—N—C + C—N—C) are 357.8° and 352.0° that show few deviations from the planar value of 360°. The more pyramidal N atom is oriented so that the corresponding lone electron pair is anti with respect to the P═O group.

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